To deduct a portion of your household energy expenses for business use, you must determine the percentage of your home that is used exclusively and regularly as a home office. This percentage is then applied to your total utility costs to calculate the deductible portion. Alternatively, the simplified method may be used, which involves a prescribed rate per square foot. Accurate records of both home expenses and the designated business area are essential. Given the intricacies of these calculations and potential limitations, it is advisable to review IRS guidelines and consult a tax professional for tailored advice.